#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>	
double huafei(int time)
{
	double sum = 0.1;
	if (time < 70)
	{
		return sum;
	}
	while (time > 70)
	{
		time -= 70;
		sum += 0.1;
	}
	return sum;
}
int main()
{
	int n = 0, i = 0, time = 0;
	double all = 0;
	scanf("%d", &n);
	for (i = 0; i < n; i++)
	{
		scanf("%d", &time);

		all += huafei(time);
	}
	printf("%.1lf", all);
	return 0;
}
